1. Technical Field
The present invention relates to a substrate for mounting a chip thereon and, more particularly, to a substrate structure for mounting a plurality of chips within a cavity.
2. Description of Related Art
In general, an LED (Light Emitting Diode), which is a semiconductor light emitting diode, draws attention in a variety fields as an environment-friendly light source that does not induce pollution. In recent years, the use range of an LED is expanded to different fields such as indoor/outdoor illumination lights, motor vehicle headlights, backlight units (BLU) of display devices, and so forth. Thus, the LED is required to have high light efficiency and superior heat dissipation characteristics. In order to obtain a high-efficiency LED, the material or structure of the LED needs to be improved first. In addition, it is necessary to improve the structure of an LED package and the material used in the LED package.
In the following descriptions, various kinds of light-emitting chips including LEDs will be referred to as an “optical element chips”. A state in which the optical element chips are mounted on a substrate will be referred to as a “chip package”. In a conventional optical element package, substrates, e.g., aluminum substrates or copper substrates are electrically insulated by a plurality of insulation layers which penetrate the substrates in an up-down direction. One-side terminals, e.g., anode terminals, of optical elements disposed on the substrates are electrically connected to the substrate of the relevant row by wires or the like. The other-side terminals, e.g., cathode terminals, of the optical elements are electrically connected by wires or the like to the substrate of the adjoining row existing beyond a vertical insulation layer. Furthermore, in order to enhance the reflection efficiency of the light reflected from the optical elements, a cavity in the form of a narrow-bottom/wide-top recess is formed across two rows of substrates which adjoin each other with a vertical insulation layer interposed therebetween. The optical elements and the wires electrically connected thereto are accommodated within the cavity.
However, in this configuration, a single chip is mounted in the central portion of the cavity. In the case of a package in which a single chip is mounted in the central portion of the cavity, if different packages are connected to one another, the overall connection becomes parallel connection. Therefore, in order to realize a backlight unit having a predetermined output power, the amount of an electric current supplied to the backlight unit needs to be increased depending on the number of packages connected to one another. This poses a problem in that the power consumption becomes larger.